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Dr. Rosemary Killen

NASA Goddard Space Flight Center

April 5, 3:30 PM

Thirkield Hall (Physics), room 103


Surface-Bounded Exospheres: What are they and why do we care?

An exosphere is a collisionless atmosphere that may extend from a denser atmosphere or from the surface of a planetary body. The source processes producing surface-bounded exospheres include interplanetary radiation, charged particles and interplanetary dust, meteoroids and asteroids that may impact the surfaces of planets and satellites. These gaseous envelopes may be bound or escaping. Exospheres that extend from atmospheres arise mainly due to Jeans escape (kinetic escape) and charge exchange with ionospheres. I will discuss the interaction of the interplanetary medium with the planets and the implications for long-term evolution of the surfaces. Exopheres from Mercury, the Moon and the satellites of the giant planets will be discussed.

Since last year's report, the "small-distance" modifications required by the quantum nature of these models is now also understood and will be presented. 



Refreshments will be served at 3:15pm